Solar heater apparatus

ABSTRACT

Solar heating apparatus that includes a solar panel having a generally rectangular box type frame that is open at the front, glass panes mounted on the frame to close the front opening and provide a dead air space, a plurality of horizontally elongated, generally rectangular tubular channels mounted with the top wall of a lower channel in abutting relationship with the bottom wall of the next higher channel, a water inlet opening through one end of the uppermost channel, a water outlet opening through one end of the lowermost channel, conduits interconnecting the channels to provide a liquid flow path serially through the channels from the uppermost channel to the lowermost channel, a heat storage reservoir, lines including a pump for pumping liquid from a heat exchanger in the storage reservoir to the panel inlet and return the liquid from the outlet to the heat exchanger, control mechanism for operating the pump in response to temperature changes in the panel, and a heat transfer system for transferring heat from the reservoir to a room or other facility to be heated. The rate of liquid flow through the panel is controlled so that only the lower portion of each channel contains liquid, for example water.

BACKGROUND OF THE INVENTION

A solar heating system that includes a solar panel.

In view of the present world energy shortage, it is desirable to providea relatively efficient solar heating system that is inexpensive tobuild. Various systems have been proposed, for example such as disclosedin U.S. Pat. No. 507,618; U.S. Pat. No. 3,236,294; U.S. Pat. No. 695,136and others. In prior art solar heating systems wherein cold water is fedinto a lowermost channel of a plurality of horizontally elongatedchannels and flows upwardly to pass through an outlet that opens to theuppermost channel, all of the channels with the possible exception ofthe uppermost channel have to be filled with water to provide for waterflow to the heat reservoir. In other systems such as U.S. Pat. No.3,236,294 water is fed into the top of a collector to flow downwardlyover corrugated aluminum. However, with such prior art systems, theefficiency of the heat transfer in the solar panel to the liquid flowingthrough the panel is not as great as desired. In order to provide for amore efficient heat transfer system and provide other advantages, thisinvention has been made.

SUMMARY OF THE INVENTION

Solar heating apparatus that includes a solar heating panel having a boxtype frame that mounts a pane of glass to close an open front of theframe, a plurality of horizontally elongated, generally rectangulartubular channels mounted in the frame between the glass pane and therear of the frame, the channels being mounted with the top wall of alower channel abutting against the bottom wall of the next uppermostchannel, conduits connecting the channels to provide flow of liquidsuccessively through the next lower channel, and a pump system fortransferring liquid between a heat reservoir and the channels, the rateof flow of liquid being controlled so that only the lower portion ofeach channel has water therein.

An object of this invention is to provide a new and novel solar panelwherein tubular channels are mounted in abutting relationship and wateris circulated from the top channel to the next lowermost channel withthe flow controlled to only partially fill each channel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of the solar panel of this invention, generallytaken along the line and in the direction of the arrow 1--1 of FIG. 2,and a diagrammatic illustration of the liquid circulation and heattransfer system connected to the panel; and

FIG. 2 is a cross-sectional view of the solar panel, said view beinggenerally taken along the line and in the direction of the arrows 2--2of FIG. 1.

Referring now to the drawings, the solar heating system of thisinvention includes a solar panel generally designated 12, the panelincluding a generally rectangular frame 13 that is open at the front andrear thereof. A plurality of open rectangular spacer subframes 14, 15and 16 are mounted in the frame, a glass pane 17 being provided betweenspacers 15 and 16 to close the front opening of frame 12. Mountedbetween subframes 14 and 15 is a glass pane 18; glass pane 17 and 18being spaced from one another and in conjunction with the subframe 15providing a closed dead air chamber 19. Suitable gaskets (not shown) maybe provided between the glass panes and subframes. The back opening offrame 13 is closed by insulation layers 23, 24; layer 24 being moreclosely adjacent pane 18 than layer 23 and being of a heat reflectivetype to minimize heat losses.

Mounted within the rectangular frame 13 are a plurality of horizontallyelongated, generally rectangular tubular channels, the tubular channelsincluding a top channel 26, a bottom channel 27 and a plurality ofintermediate channels 28. The top wall 29 of the channel 27 abutsagainst the bottom wall 30 of the adjacent intermediate channel whilethe bottom wall of each of the other channels abuts against the top wallof the channel therebeneath. Preferably the height of each channel issubstantially greater than the width thereof. These channels are mountedin a frame 12 to provide a dead air chamber 20 between the pane 18 andsaid channels. Further, advantageously the back walls of the channelsabut against the insulating layer 24.

Each of the channels has end walls 25 closing the end thereof, a waterinlet 31 being provided to pass through the subframe 14 and frame andopen through one end wall of the top channel 26 to open to the interiorthereof. Likewise a water outlet 34 opens through the subframe and frameto open to one end wall of the bottom channel 27 to open to the interiorthereof. If an even number of channels are provided such as illustratedin the drawings, then conduits 33 are provided for each set ofvertically adjacent pairs of intermediate channels, each conduit openingthrough the one end wall of the upper one of the respective pair forconducting liquid to the intermediate channel therebeneath, such asshown in FIG. 1. Further, there are provided conduits 32 that openthrough the opposite end walls of the channels such as shown in FIG. 1.That is, advantageously the channels are connected to provide a serialflow through the channels with the liquid passing through inlet 31 intoone end of the top channel 26 to pass therethrough and be conducted byconduit 32 to the opposite end of channel 27 that is immediatelytherebeneath, pass through the uppermost intermediate channel 27 to theone end thereof and be conducted by a conduit 33 to the one end of thenext lower channel and etc. to ultimately be discharged through outlet34. The inlet 31, the outlet 23, and inlets and outlets of the conduits32 and 33 open to only the lower portion of the respective channel,i.e., the openings not extending above the lower half of the respectivechannel, and preferably not even that high in the respective channel.This provides a dead air space in each channel above the level of theliquid in the respective channel.

A check valve 36 is mounted on a frame to open through the top wall ofthe uppermost channel into the interior thereof, the check valvepermitting the passage of air into the interior of the uppermost channelwhen a vacuum develops therein, but prevents passage of fluid in theopposite direction. The provision of the check valve 36 facilitatesdraining water from the channels.

A pressure relief valve 37 is mounted on the frame to open through thetop wall of the top channel, the relief valve being provided toautomatically open in the event that there is any substantial buildup ofsteam or air pressure in the top channel.

For storing heat energy collected by the solar panel, there is provideda heat reservoir or heat storage bin 48 which preferably is a largeconcrete block that is surrounded by one or more layers of heatreflective insulation (not shown) to minimize the loss of heattherefrom. Located within the block is a heat transfer unit 47 whichadvantageously may be a plurality of heat transfer tubes connected inend to end relationship and spaced from one another within the block.One end of the heat transfer unit 47 is connected by a liquid conductingline 46 to outlet 34 while the opposite end is connected to inlet 31 bya liquid conduit 49. Located within line 49 is a pump 50 and a shut-offvalve 51. The pump is provided for circulating liquid through lines 46,49, and heat exchanger 47 to flow in a direction to pass through inlet31 and thence through the channels to exit through outlet 34.

For transferring heat from the heat reservoir 48 to the place of use, aheat transfer unit 56 is provided in the heat reservoir and connected bylines 57 to the heat transfer unit 58 that is located in a place that isto be heated, for example in the hot air system of a house. Appropriatethermostatic controls 59 are connected to the heat transfer unit 58 forcontrolling heat transfer from the heat storage unit 48 and through theheat transfer unit 58 to the place that it is to be used. The heatreservoir can be located in any suitable location, for example buried inthe ground outside of a house, or in the basement of the house or etc.Since members 47, 48 and 56-59 may be of a conventional construction,the construction thereof will not be further described.

In using the apparatus of this invention, the solar panel 12 is mountedin a suitable location, for example on the south slope of a roof or ahouse or may be located in the yard. Preferably the panel is mounted ona suitable stand whereby its angle with reference to the sun may bevaried to obtained the maximum heat energy from the sun, and inconnection therewith, suitable conventional stands may be used. When thetemperature within chamber 20 exceeds a preselected minimum, for exampleabout 120° F., controls 54 will automatically turn on pump 50 to pumpwater through the inlet 31 into the top channel and thence through thechannel to the top conduit 32 and thence downwardly to the next lowerchannel and etc. until the water flows through the outlet 34 and thencethrough the transfer unit 47 wherein the heat is transferred from thewater to the block 48. The water thence returns through line 49 to thepump. The pumping of water into the top channel may result in a buildupof pressure in the channels; however, the buildup is not sufficientlygreat to result in air discharging through the valve 37. The flow rateof water through the panel is controlled so that the height of the waterin each channel is less than one-half of the maximum vertical dimensionof the channel, the maximum vertical dimension varying with the angle ofinclination of the panel providing rectangular channels are used. Thisprovides a dead air space between the top surface of the water and theuppermost portion of the channel and accordingly the walls of thechannel above the liquid level are not unduly cooled as the water passestherethrough. The top wall of any of the channels below the top channeltransfer heat through the adjacent bottom wall of the next uppermostrespective channel wherein it is transferred to the liquid flowingtherethrough. Thus, the heat in any one channel above the liquid levelin the respective channels flows in part downwardly through the channelto the surface of the channel contacted by liquid, and in part flowsupwardly through the walls of the channel to the top wall of therespective channel to the bottom wall of the next uppermost channel andthence is transferred to the liquid flowing through said next uppermostchannel. This transfer of heat serves to prevent the channels from beingtoo hot at the top and too cold at the bottom.

In the event that the water at the outlet 34 is above a giventemperature, for example 160° F., the flow rate of the water isincreased to remove a greater amount of heat from the channels topreclude any substantial amount of steam forming in the panel. Asuitable temperature sensor (not shown) may be connected from the outletto the controls 54 to control the speed of the pump, provided the pumpis a variable speed pump, or through appropriate electronic andhydraulic controls the flow rate of the water through the channels mayotherwise be controlled. When the temperature in chamber 20 falls belowa predetermined level, for example 120° F., the controls 54automatically shut off pump 50.

At the time heat is required in the house or other facility beingheated, the controls 59 will automatically actuate the transfer system58 whereby fluid flows through line 57 and heat transfer unit 56 toremove heat from block 48 and give off heat in the heating system of thehouse.

Preferably the channels are made of steel; however, other materials, forexample, aluminum can be used. As an example of the invention but not asa limitation thereof, the channels can be 2 inch by 6 inch channels ofappropriate length, the inlet and outlet of each channel can bethree-quarter inch O.D. pipe, and the rate of flow of liquid through thechannels can be about two gallons per minute.

It is to be understood that in place of a plurality of individualtubular channels, channels can be made by a pair of parallel steel metalplates that have parallel dividers extending therebetween to form otherchannels of construction such as generally illustrated in FIG. 2,whereby one divider wall would form the top wall of one channel and alsothe bottom wall of the channel thereabove.

What is claimed is:
 1. Solar heating apparatus comprising a solar panelhaving a perimetric frame that has an upper wall, a lower wall, an openfront side, and an open back side, first means joined to the frame toclose the back side opening, second means that permits passage ofinfrared rays of the sun mounted on the frame in substantial spacedrelationship to the first means to close the front side opening, wallmeans defining a plurality of horizontally elongated tubular fluidchannels with one extending vertically above the other mounted in theframe between the first and second means and spaced from the secondmeans, each channel having a top wall portion, a bottom wall portion, afirst end wall and a second end wall, a liquid inlet opening to theinterior of the vertically uppermost fluid channel adjacent the firstend wall thereof, a liquid outlet opening to the interior of thevertically lowermost fluid channel adjacent one of the end wallsthereof, and conduit means opening to interiors of the fluid channelsadjacent the end walls thereof other than the ones adjacent the liquidinlet and liquid outlet for interconnecting the channels to provide aliquid flow path between the channels from the liquid inlet to theliquid outlet with the liquid flowing in a direction through a channelthat is opposite the direction of flow through the channel immediatelyvertically therebeneath, means remote from the panel for storing heatenergy, and means for conducting liquid from the liquid outlet to theheat storing means and from the heat storing means to the liquid inletwhereby liquid from the heat storing means passes through the liquidinlet and along the liquid flow path to the liquid outlet, the liquidconnecting means including means for controlling the flow of liquidthrough the liquid inlet to maintain liquid in each channel at a levelthat is a substantial distance below the top wall portion of therespective channel to provide a dead air space in each channel above thelevel of the liquid in the respective channel.
 2. The apparatus of claim1 further characterized in that the conduit means includes for eachchannel other than the lowermost channel a discharge opening that opensto the interior of the respective channel vertically more closelyadjacent the bottom wall portion of the respective channel than the topwall portion thereof, and includes for each channel an inlet openingthat opens to the interior of the respective channel vertically moreclosely adjacent the bottom wall portion of the respective channel thanthe top wall portion thereof.
 3. The apparatus of claim 2 furthercharacterized in that each of the channels is a generally rectangularmetal channel, and that the bottom wall portion of the uppermost channelis in abutting relationship to the top wall portion of the channelvertically therebeneath.
 4. Solar heating apparatus comprising a solarpanel having a plurality of horizontally elongated, generallyrectangular, tubular liquid channels with the channels being onegenerally vertically above the other, each channel having a first endwall portion, a horizontally opposite second end wall portion, a topwall portion and a bottom wall portion, the bottom wall portion of eachchannel that is vertically above another being in contact with the topwall portion of the channel immediately therebeneath, perimetric framemeans for mounting said channels, means cooperating with the frame meansfor providing a dead air chamber that opens to the channels, thecooperating means including means that permits passage of infrared raysof the sun to pass through the dead air chamber and impinge on thechannels, a liquid inlet opening through the first end wall of theuppermost channel to the interior thereof, a liquid outlet openingthrough one of the end walls of the lowermost channel to the interiorthereof at a location more closely adjacent the bottom wall portion ofthe lowermost channel than the top wall portion thereof and means forfluidly connecting the channels in series to provide a fluid flow pathfrom the liquid inlet through the uppermost channel and sequentiallythrough each next lower channel to the liquid outlet, the seriesconnecting means having an opening through which liquid is dischargedfrom the respective channel that is more closely adjacent the bottomwall portion of the respective channel than the top wall portionthereof, a heat storage receptacle, and means to conduct liquid from theliquid outlet to said storage receptacle, give up heat energy to thereceptacle and conduit liquid to the liquid inlet, and control meansconnected to the liquid conduit means for regulating the rate of flow ofliquid to the liquid inlet to an amount that the liquid in each of thechannels remains at a level substantially below the top wall portionthereof.
 5. The apparatus of claim 4 further characterized in that theconduit means includes a pump, that the control means includes a controlfor turning the pump on when the temperature in the dead air chamberexceeds a preselected value and turning the pump off when thetemperature in the dead air chamber falls below a preselected value. 6.The apparatus of claim 4 further characterized in that there is providedvalve means opening to the uppermost channel to permit air flowthereinto when a vacuum develops therein and permit discharge therefromwhen the pressure in the uppermost channel exceeds a preselected value.7. The apparatus of claim 4 further characterized in that the panelincludes means that permits the passage of infrared rays mounted on theframe means to provide a dead air chamber opposite the first dead airchamber from the channels, that the control means controls the rate offlow in the channels to a level that each channel is less than half fullof liquid and that each liquid opening and discharge opening for eachchannel opens only to the lower half of the respective channel.